Understanding the Difference Between a Regular and Dense Breast Tissue

Women are diagnosed with dense fibrous breast tissue based on the balance between two main types of tissue in the breast. One type is glandular tissue, which is the working part of the breast, and the other is the fatty layer that sits just under the skin.

When a woman has more glandular tissue than fatty tissue, her breasts are considered dense. Density can vary—some women have moderately dense breasts, while others have extremely dense breasts.

In the ultrasound image of a dense breast, you can clearly see that the glandular tissue layer is larger than the fatty layer. The image also shows that the ultrasound probe (called a transducer) can see all the way down to the ribs, which confirms that every layer of the breast has been examined. Seeing the breast from the skin all the way to the chest wall is very important for a thorough evaluation.

Dense breast tissue can also make cancer harder to detect, especially on a mammogram. Both dense glandular tissue and tumors tend to appear white on a mammogram image. Because they look similar, a tumor can sometimes blend in with the surrounding dense tissue and be more difficult to see. It is a bit like trying to find a snowball in a snowstorm—the shapes can look very similar.

This is one reason why additional imaging, such as breast ultrasound, can be helpful for women with dense breasts. Ultrasound looks at the breast tissue in a different way and can often help distinguish between normal dense tissue, fluid-filled cysts, and solid masses.

At OC Breast Wellness, ultrasound allows our technicians to carefully examine the breast layer by layer. This technology helps us better visualize the glandular tissue where most breast cancers begin and gives us another important tool to help identify abnormalities that may not be visible on a mammogram alone.